In order to delineate the areas of altered central neurophysiologic functioning which underlie the acute symptomatology of the functional psychoses, a large number of cerebral evoked response (CER) and EEG measures will be followed over the period of clinical change during drug treatment in both depressive, manic and schizophrenic populations. The CER and EEG variables which change during treatment or which correlate to symptomatology will be further investigated in drug studies on normal subjects. In addition, intracerebral recording in animals will be carried out to provide more detailed information of the relevant drug effects on neurophysiologic measurements homologous to those recorded in man.